Magnetoresistance effect element, magnetic head and magnetic reproducing system

ABSTRACT

There is provided a magnetoresistance effect element capable of precisely defining the active region in a CPP type MR element and of effectively suppressing and eliminating the influence of a magnetic field due to current from an electrode, and a magnetic head and magnetic reproducing system using the same. The active region of the MR element is defined by the area of a portion through which a sense current flows. Moreover, the shape of the cross section of a pillar electrode or pillar non-magnetic material for defining the active region of the element is designed to extend along the flow of a magnetic flux so as to efficiently read only a signal from a track directly below the active region. When the magnetic field due to current from the pillar electrode can not be ignored, the magnetic flux from a recording medium asymmetrically enters yokes and the magnetization free layer of the MR element to some extent. In expectation of this, if the cross section of the pillar electrode is designed to be asymmetric so as to extend along the flow of the magnetic flux, the regenerative efficiency is improved.

CROSS REFERENCE TO RELATED APPLICATION

[0001] This application is based upon and claims the benefit of priorityfrom the prior Japanese Patent Applications No. 2000-301118, filed onSep. 29, 2000; the entire contents of which are incorporated herein byreference.

BACKGROUND OF THE INVENTION

[0002] 1. Field of the Invention

[0003] The present invention generally relates to a magnetoresistanceeffect element, a magnetic head and a magnetic reproducing system. Morespecifically, the invention relates to a magnetoresistance effectelement for causing a sense current to flow in a direction perpendicularto the plane of the element to detect an external magnetic field, amagnetic head using the same, and a magnetic reproducing system usingthe same.

[0004] 2. Description of Related Art

[0005] Conventionally, the readout of magnetic information recorded in amagnetic recording medium has been carried out by a method forrelatively moving a reproducing magnetic head having a coil with respectto the recording medium to generate an electromagnetic induction todetect a voltage which is induced in the coil by the electromagneticinduction. On the other hand, an electromagnetic effect element (whichwill be hereinafter referred to as an “MR element”) has been developed.The electromagnetic effect element is being used for a magnetic sensor,and mounted on a magnetic head (which will be hereinafter referred to asan MR head) for use in a magnetic reproducing system, such as a harddisk drive.

[0006] In recent years, the size of a magnetic recording medium isdecreasing, and the capacity thereof is increasing, so that the relativevelocity of a reproducing magnetic head to the magnetic recording mediumis decreasing during the readout of magnetic information. For thatreason, it is required to provide an MR head capable of taking out alarge output even if the relative velocity is small.

[0007] According to such a request, it has been reported that amultilayer film, such as Fe/Cr or Fe/Cu, wherein ferromagnetic metalfilms and magnetic metal films are alternately stacked on certainconditions, i.e., a so-called “artificial lattice film”, has a giantmagnetoresistance effect (see Phys. Rev. Lett. 61 2474 (1988), Phys.Rev. Lett. 64 2304 (1990)). However, since magnetization is saturated inthe artificial lattice film, a required magnetic field is high therein,so that the artificial lattice film is not suitable for the material ofa film for an MR head.

[0008] On the other hand, there has been reported an example where alarge magnetoresistance effect was realized even if a ferromagneticlayer is not antiferromagnetically connected in a multilayer film havinga sandwich structure of ferromagnetic layer/non-magneticlayer/ferromagnetic layer. That is, a magnetic field due to exchangebias is applied to one of two ferromagnetic layers, which sandwich anon-magnetic layer therebetween, to fix magnetization, and themagnetization of the other ferromagnetic layer is inverted by anexternal magnetic field (a magnetic field due to signal or the like).Thus, by changing the relative angle between the magnetizing directionsof the two ferromagnetic layers which sandwich the non-magnetic layertherebetween, a large magnetoresistance effect is obtained. A multilayerfilm of such a type is called a “spin-valve” (see Phys. Rev. B 45 806(1992), J. Appl. Phys. 69 4774 (1981)). Since the spin-valve cansaturate magnetization in a low magnetic field, the spin-valve issuitable for MR heads. However, since the rate of change in magneticresistance of elements which have been already put to practical use isonly about 20% at the maximum, it is required to improve the rate ofchange in magnetic resistance.

[0009] By the way, most of conventional MR elements have a type whereina sense current is caused to flow in a direction parallel to the planeof an MR film constituting the MR element. This is called “CIP (currentin plane)”. On the other hand, there is an MR element wherein a sensecurrent is caused to flow in a direction perpendicular to the plane ofan MR film. This is called “CPP (current perpendicular to plane)”. Ithas been reported that CPP can obtain a rate of change in magneticresistance ten times as large as that of CIP (J. Phys. Condens. Matter.11 5717 (1999)), and it is not impossible to obtain a rate of change of100%.

[0010] However, if a sense current is caused to flow in a directionperpendicular to the plane of the MR film, there is a problem in thatthe electric resistance is very small, so that the output decreases.Therefore, it has been attempted to decrease the area itself of the MRfilm to raise the value of resistance to increase the output (Phys. Rev.Lett. 70 3343 (1993)). However, in the method for decreasing the areaitself of the MR film, it is limited to cause the MR film to be a singlemagnetic domain.

[0011] In addition, if a sense current is caused to flow in a directionperpendicular to the plane of the MR film, an annular magnetic field dueto current is generated in the plane of the MR film. This annularmagnetic field causes to prevent a magnetization free layer, in whichmagnetization rotates with respect to the magnetic field due to signal,from being a single magnetic domain.

[0012] On the other hand, most of conventional MR heads have a“shielded” construction wherein an MR film is sandwiched betweenshields. In the case of the shielded construction, a floating magneticfield from a magnetic recording medium is directly detected by aspin-valve. However, in recent years, the recording density is furtherenhanced, so that a “yoke type” head for efficiently incorporating amagnetic flux from a magnetic recording medium into a magnetization freelayer of a spin-valve via a magnetic flux guide (yoke) once has beenproposed.

[0013] However, after the inventor's study, it was revealed that, inmany magnetic heads represented by yoke type magnetic heads, it isrequired to define an active region, in which the detection of magnetismof an MR film is carried out, for various reasons.

[0014] As an example of this circumstance, a “planar type” head of yoketype heads will be described below.

[0015]FIG. 31 is a schematic perspective view showing the constructionof a principal part of a planar type head. That is, the planar type headhas a construction that a pair of flat yokes 20, 20 are arranged inparallel to the plane of a recording media 200. An MR film 100constituting an MR element is provided so as to be magnetically coupledto the yokes 20, 20.

[0016] The recording medium 200 is provided with recording bits 200Balong a recording track 200T. The magnetic flux due to signal from eachof the recording bits 200B is supplied to a magnetic circuit, which isformed by the yoke 20, the MR film 100 and the yoke 20, to be detected.According to such a planar type construction, the length of a magneticpath to the MR film 100 is shortened, so that the magnetic flux can beefficiently led to a spin-valve (see IEEE Trans. Mag. 25, 3689 (1989)).

[0017] However, the width 20W of the yoke 20 of the planar type head iswider than the width 200W of the recording track 200T of the recordingmedium which has been acceleratively narrowed in recent years. For thatreason, it is required to limit the active region of the MR film 100 foractually reading the magnetic flux.

[0018] In addition, in the planar type head, it is desired that themagnetic permeability is uniform and great so that the magnetic flux dueto signal from the recording medium 200 efficiently enters the yoke 20without being asymmetric and further enters the magnetization free layerof the MR film 100. Therefore, if a pair of magnetically hard materials30, 30 are arranged so as to be perpendicular to the longitudinaldirections of the track 200T of the medium so that the magnetization ofthe yoke 20 and the magnetization free layer is perpendicular to thetrack direction, the magnetic permeability can be high and uniform.

[0019] However, if a CPP type MR element for realizing a highmagnetoresistance effect is used, it is required to provide an electrodeportion (pillar electrode) for causing a sense current to flow throughthe MR film in a direction perpendicular thereto. If an annular magneticfield due to current from this electrode portion exceeds a magnetizationfixing force due to the pair of magnetically hard materials 30, 30, themagnetization distribution of the magnetization free layer of the yoke20 and the MR film 100 varies, so that the magnetic permeability is notuniform.

[0020] Moreover, if the CPP type MR element is used, the MR film 100 issandwiched between top and bottom electrodes (not shown). Therefore, itwas revealed that the magnetic field due to current from a portion ofthese electrodes parallel to the MR film 100 also influences themagnetization distribution in the yoke 20 and the magnetization freelayer of the MR film 100.

[0021] The above described problems are not only caused in the planartype heads, but the problems are also commonly caused in most of yoketype heads or heads having other structures. For example, the sameproblems are caused in the “shielded” heads.

SUMMARY OF THE INVENTION

[0022] It is therefore an object of the present invention to eliminatethe aforementioned problems and to provide a magnetoresistance effectelement capable of precisely defining the active region of an MR film ina CPP type MR element and of effectively suppressing the influence of amagnetic field due to current from an electrode, and a magnetic head andmagnetic reproducing system using the same.

[0023] In order to accomplish the aforementioned object, according to afirst aspect of the present invention, a magnetoresistance effectelement comprises: a magnetization fixed layer in which the direction ofmagnetization is substantially fixed to one direction; a magnetizationfree layer in which the direction of magnetization varies in response toan external magnetic field; and a non-magnetic intermediate layer formedbetween the magnetization fixed layer and the magnetization free layer,the magnetoresistance effect element having a resistance varying inresponse to a relative angle between the direction of magnetization inthe magnetization fixed layer and the direction of magnetization in themagnetization free layer, the film area of the non-magnetic intermediatelayer being smaller than the film area of each of the magnetizationfixed layer and the magnetization free layer, and a sense currentdetecting the variation of the resistance being applied to the filmplanes of the magnetization fixed layer, the non-magnetic intermediatelayer and the magnetization free layer in a direction substantiallyperpendicular thereto.

[0024] According to a second aspect of the present invention, amagnetoresistance effect element comprises: a stacked film including amagnetization fixed layer in which the direction of magnetization issubstantially fixed to one direction, and a magnetization free layer inwhich the direction of magnetization varies in response to an externalmagnetic field; and an electrode connected to a part of a principalplane of the stacked film, the magnetoresistance effect element having aresistance varying in response to a relative angle between the directionof magnetization in the magnetization fixed layer and the direction ofmagnetization in the magnetization free layer, a sense current detectingthe variation of the resistance being applied to the film planes of themagnetization fixed layer and the magnetization free layer via theelectrode in a direction substantially perpendicular to themagnetization fixed layer and the magnetization free layer, and theelectrode comprising a pillar electrode portion substantiallyperpendicularly extending from the principal plane of the stacked film,a first feed portion being connected to the pillar electrode portion andextending from the pillar electrode portion substantially in parallel tothe principal plane of the stacked film, and a second feed portion beingconnected to the first feed portion and extending from the first feedportion substantially in parallel to the principal plane.

[0025] According to a third aspect of the present invention, amagnetoresistance effect element comprises: a stacked film including amagnetization fixed layer in which the direction of magnetization issubstantially fixed to one direction, and a magnetization free layer inwhich the direction of magnetization varies in response to an externalmagnetic field; and two electrodes, each of which is connected to a partof a corresponding one of both principal planes of the stacked film, themagnetoresistance effect element having a resistance varying in responseto a relative angle between the direction of magnetization in themagnetization fixed layer and the direction of magnetization in themagnetization free layer, a sense current detecting the variation of theresistance being applied to the film planes of the magnetization fixedlayer and the magnetization free layer via the electrode in a directionsubstantially perpendicular to the magnetization fixed layer and themagnetization free layer, and each of the two electrodes comprising apillar electrode portion substantially perpendicularly extending fromthe corresponding one of the both principal planes of the stacked film,a first feed portion being connected to the pillar electrode portion andextending from the pillar electrode portion substantially in parallel tothe both principal planes of the stacked film, and a second feed portionbeing connected to the first feed portion and extending from the firstfeed portion substantially in parallel to the both principal planes.

[0026] According to a fourth aspect of the present invention, amagnetoresistance effect element comprises: a stacked film including amagnetization fixed layer in which the direction of magnetization issubstantially fixed to one direction, and a magnetization free layer inwhich the direction of magnetization varies in response to an externalmagnetic field; and an electrode connected to a part of a principalplane of the stacked film, the magnetoresistance effect element having aresistance varying in response to with a relative angle between thedirection of magnetization in the magnetization fixed layer and thedirection of magnetization in the magnetization free layer, a sensecurrent detecting the variation of the resistance being applied to thefilm planes of the magnetization fixed layer and the magnetization freelayer via the electrode in a direction substantially perpendicular tothe magnetization fixed layer and the magnetization free layer, and theelectrode comprising a pillar electrode portion substantiallyperpendicularly extending from the principal plane of the stacked film,and a feed portion extending substantially in parallel to the principalplane of the stacked film, the pillar electrode portion having twoconductive layers in the central portion and outer peripheral portionthereof, and the sense current being caused to flow in the oppositedirections to each other in the central portion and the outer peripheralportion.

[0027] According to a fifth aspect of the present invention, amagnetoresistance effect element comprises: a stacked film including amagnetization fixed layer in which the direction of magnetization issubstantially fixed to one direction, and a magnetization free layer inwhich the direction of magnetization varies in response to an externalmagnetic field; and an electrode connected to a part of a principalplane of the stacked film, the magnetoresistance effect element having aresistance varying in response to a relative angle between the directionof magnetization in the magnetization fixed layer and the direction ofmagnetization in the magnetization free layer, a sense current detectingthe variation of the resistance being applied to the film planes of themagnetization fixed layer and the magnetization free layer via theelectrode in a direction substantially perpendicular to themagnetization fixed layer and the magnetization free layer, and theelectrode comprising a pillar electrode portion substantiallyperpendicularly extending from the principal plane of the stacked film,and a feed portion extending substantially in parallel to the principalplane of the stacked film, the magnetoresistance effect element furthercomprising a magnetic shield provided around the pillar electrodeportion.

[0028] According to a sixth aspect of the present invention, a magnetichead comprises: a pair of yokes arranged so as to face each other via amagnetic gap; and a magnetoresistance effect element magneticallycoupled to the pair of yokes, the pair of yokes having magnetizationarranged in a predetermined direction, and the magnetoresistance effectelement comprising: a stacked film including a magnetization fixed layerin which the direction of magnetization is substantially fixed to onedirection, and a magnetization free layer in which the direction ofmagnetization varies in response to an external magnetic field; and anelectrode connected to a part of a principal plane of the stacked film,the magnetoresistance effect element having a resistance varying inresponse to a relative angle between the direction of magnetization inthe magnetization fixed layer and the direction of magnetization in themagnetization free layer, a sense current detecting the variation of theresistance being applied to the film planes of the magnetization fixedlayer and the magnetization free layer via the electrode in a directionsubstantially perpendicular to the magnetization fixed layer and themagnetization free layer, and the shape of a connecting portion forconnecting the principal plane to the electrode having an edge portionbeing inclined in a magnetization rotating direction of themagnetization free layer from a direction perpendicular to themagnetizing direction of the yokes.

[0029] According to a seventh aspect of the present invention, amagnetic head comprises: a pair of yokes arranged so as to face eachother via a magnetic gap; and a magnetoresistance effect elementmagnetically coupled to the pair of yokes, the pair of yokes havingmagnetization being arranged in a predetermined direction, and themagnetoresistance effect element comprising: a first stacked filmincluding a magnetization fixed layer in which the direction ofmagnetization is substantially fixed to one direction; a second stackedfilm including a magnetization free layer in which the direction ofmagnetization varies in response to an external magnetic field; and anon-magnetic intermediate layer provided between the first stacked layerand the second stacked layer, the magnetoresistance effect elementhaving a resistance varying in response to a relative angle between thedirection of magnetization in the magnetization fixed layer and thedirection of magnetization in the magnetization free layer, the area ofa contact portion of a principal plane of the first stacked filmcontacting the non-magnetic intermediate layer being smaller than thearea of the principal plane of the first stacked film, and the area of acontact portion of a principal plane of the second stacked filmcontacting the non-magnetic intermediate layer being smaller than thearea of the principal plane of the second stacked film, a sense currentdetecting the variation of the resistance being applied to the filmplanes of the magnetization fixed layer, the non-magnetic intermediatelayer and the magnetization free layer in a direction substantiallyperpendicular thereto, the shape of a connecting portion for connectingthe non-magnetic intermediate layer to the principal plane of the firststacked film having an edge portion being inclined in a magnetizationrotating direction of the magnetization free layer from a directionperpendicular to the magnetizing direction of the yokes.

[0030] According to an eighth aspect of the present invention, amagnetic head comprises: a pair of yokes being arranged so as to faceeach other via a magnetic gap; and a magnetoresistance effect elementprovided on the pair of yokes and magnetically coupled to the pair ofyokes, the pair of yokes having magnetization arranged in apredetermined direction, and the magnetoresistance effect elementcomprising: a stacked film including a magnetization fixed layer inwhich the direction of magnetization is substantially fixed to onedirection, and a magnetization free layer in which the direction ofmagnetization varies in response to an external magnetic field; a topelectrode connected to a part of an upper principal plane of the stackedfilm; a bottom electrode connected to a lower principal plane of thestacked film, the magnetoresistance effect element having a resistancevarying in response to a relative angle between the direction ofmagnetization in the magnetization fixed layer and the direction ofmagnetization in the magnetization free layer, a sense current detectingthe variation of the resistance being applied to the film planes of themagnetization fixed layer and the magnetization free layer via theelectrode in a direction substantially perpendicular to themagnetization fixed layer and the magnetization free layer, the topelectrode having a pillar electrode portion substantiallyperpendicularly extending from the principal plane of the stacked film,and a feed portion extending substantially in parallel to the principalplane of the stacked film, the bottom electrode extending in a directionperpendicular to the direction of magnetization of the yokes, the feedportion of the top electrode being provided so that the sense currentflowing through the feed portion is anti-parallel to a sense currentflowing through the bottom electrode.

[0031] In the magnetic head according to any one of the above describedsixth through eighth aspects, a method for applying magnetization, whichis arranged in a predetermined direction, to the pair of yokes may be amethod for annealing the yokes in a magnetic field, or a method forapplying a magnetic field due to bias which is caused by a biasing filmof a magnetically hard film or an antiferromagnetic film.

[0032] According to a ninth aspect of the present invention, a magnetichead has a magnetoresistance effect element according to any one of theabove described first through fifth aspect.

[0033] According to a tenth aspect of the present invention, a magneticreproducing system has any one of the above described magnetic head, andis capable of reading magnetic information stored in a magneticrecording medium.

[0034] In other words, according to another aspect of the presentinvention, a magnetoresistance effect film wherein a current is appliedto the element in a direction perpendicular to the film surface of theelement and which comprises: at least one magnetization free layer inwhich magnetization rotates in response to an external magnetic field;and at least one magnetization pinned layer in which magnetization isfixed, wherein a pillar electrode is provided between a portion forallowing a sense current to flow in parallel to the film surface of theelement of the electrode and the element, the sectional area of aportion of the pillar electrode contacting the element being smallerthan the area of any portion of the element.

[0035] According to another aspect of the present invention, amagnetoresistance effect film wherein a current is applied to theelement in a direction perpendicular to the film surface of the elementand which comprises: at least one magnetization free layer in whichmagnetization rotates in accordance with an external magnetic field; andat least one magnetization pinned layer in which magnetization is fixed,wherein a pillar electrode is provided between a portion for allowing asense current to flow in parallel to the film surface of the element ofthe electrode and the element, the sectional area of a portion of thepillar electrode contacting the element being smaller than the area ofany portion of the element if being viewed from an approaching directionof a magnetic field due to signal or a direction perpendicular to theapproaching direction.

[0036] In the magnetoresistance effect element according to the secondaspect, the sectional area of the pillar portion may substantiallylinearly increase from a surface contacting the element toward a surfaceof a portion in which a current flows in parallel and which contacts theelectrode.

[0037] Alternatively, in the magnetoresistance effect element accordingto the second aspect, the sectional area of the pillar portion maysimply increase from a surface contacting the element toward a surfacein which a current flows in parallel to the film surface of the elementand which contacts the electrode, and its increasing rate may vary onthe way.

[0038] Alternatively, in the magnetoresistance effect element accordingto the second aspect, the pillar portion may be divided into twoportions having a small rate of change in sectional area.

[0039] Moreover, the contact area of the pillar portion contacting themagnetoresistance effect film may be S_(Lead)/S_(MR)>2000 assuming thatthe contact area of the pillar portion contacting the feed portion isS_(Lead).

[0040] Alternatively, of the two portions having the small rate ofchange in sectional area, the height of a portion having a small meansectional area may be 30 nm or less.

[0041] In addition, the electrode area of a portion of the bottom andtop electrodes contacting the pillar electrode may be narrowed so as tobe the same as the sectional area of the pillar electrode.

[0042] That is, in the case of a CPP element, the active region of theMR element is defined by the area of a portion, in which a sense currentflows, of a ferromagnetic/non-magnetic interface which mainly providesthe magnetoresistance effect element. In the case of a CPP type MR, thesectional area of the pillar electrode must be smaller than the size ofthe element in order to increase the electrical resistance whilemaintaining the magnetic characteristics of the MR element. By thepillar electrode in this case, the active region of the MR element canbe defined.

[0043] In addition, in order to decrease the magnetic field due tocurrent from the pillar electrode, the sectional area of the pillarelectrode is varied to decrease the area of a surface contacting theelement. Moreover, the pillar electrode is formed by two portions inwhich the sectional area does not so vary, and the sectional area andheight of a portion contacting the element are defined to bepredetermined ranges. If the magnetic field due to current from thepillar electrode is decreased to be smaller than the magnetizationfixing force due to a pair of magnetically hard materials, themagnetization in the yokes and the magnetization free layer of the MRelement does not so rotate. For that reason, the magnetic flux from therecording medium substantially symmetrically enters the magnetizationfree layer.

[0044] Alternatively, the sense current is caused to go and return inthe pillar electrode to prevent the magnetic field due to current frombeing applied, so that the magnetic field due to the sense current iscanceled. Alternatively, a magnetic shield is provided around the pillarelectrode to prevent the magnetic field due to current from beingapplied to the element. If the current is caused to go and return in thepillar electrode, the magnetic field due to current to the outside ofthe electrode is canceled. In addition, if the shield is provided, themagnetic field due to current is not applied to the element and theyokes. Therefore, the magnetic flux from the recording mediumsymmetrically enter the magnetization free layer.

[0045] Moreover, in the case of a planar yoke head, the magnetization ofthe yokes may rotate due to the influence of the magnetic field due tocurrent which could not have been removed. In this case, there is somepossibility that the magnetization of the yokes may be deviated from adirection parallel to the track longitudinal direction of the recordingmedium to read a magnetic flux due to signal from an adjacent track. Inorder to prevent this, the shape of the cross section of the pillarelectrode or the pillar non-magnetic material for defining the activeregion of the element is designed to extend along the flow of themagnetic flux so as to efficiently read only a signal from a trackdirectly below the active region. When the magnetic field due to currentfrom the pillar electrode can not be ignored, the magnetic flux from therecording medium asymmetrically enters the yokes and the magnetizationfree layer of the MR element to some extent. In expectation of this, ifthe cross section of the pillar electrode is designed to be asymmetricso as to extend along the flow of the magnetic flux, the regenerativeefficiency is improved.

[0046] In addition, the electrode is arranged so that the currentapplying direction in an electrode portion parallel to the plane of theelement is parallel to the track direction of the medium. According tosuch an arrangement, the direction of the magnetic field due to currentfrom this portion is the same direction as the magnetization fixingdirection of the yokes and magnetization free layer due to the pair ofmagnetically hard materials. In addition, if the direction of current inthe top electrode is anti-parallel to that in the bottom electrode, themagnetic field due to current applied to the yokes can be reduced. Ifthe electrode in a portion parallel to the plane of the element isparallel to the track direction, the magnetic field due to current isgenerated in a direction perpendicular to the track. Since thisdirection is the same as the magnetization fixing direction due to thepair of magnetically hard materials, there is no influence on themagnetization distribution in the yokes and magnetization free layer.

BRIEF DESCRIPTION OF THE DRAWINGS

[0047] The present invention will be understood more fully from thedetailed description given herebelow and from the accompanying drawingsof the embodiments of the invention. However, the drawings are notintended to imply limitation of the invention to a specific embodiment,but are for explanation and understanding only.

[0048] In the drawings:

[0049] FIGS. 1(a) and 1(b) are sectional and plan views showing thefirst embodiment of a magnetoresistance effect element according to thepresent invention;

[0050]FIG. 2 is a conceptual drawing showing a first modified example ofa magnetoresistance effect element in the first embodiment;

[0051]FIG. 3 is a conceptual drawing showing a second modified exampleof a magnetoresistance effect element in the first embodiment;

[0052]FIG. 4 is a conceptual drawing showing a current path in amagnetoresistance effect film 13;

[0053]FIG. 5 is a conceptual drawing showing a sectional construction ofa third modified example of a magnetoresistance effect element in thefirst embodiment;

[0054]FIG. 6 is a conceptual drawing showing a principal part of ashielded head on which the magnetoresistance effect element illustratedin FIG. 1 is mounted;

[0055]FIG. 7 is a conceptual drawing showing a magnetizationdistribution in a magnetization free layer (free layer) of amagnetoresistance effect element;

[0056]FIG. 8 is a perspective view showing a construction wherein themagnetoresistance effect element illustrated in FIG. 1 is mounted on aplanar yoke head;

[0057]FIG. 9 is a conceptual drawing showing a magnetizing direction inthe third embodiment of a head according to the present invention;

[0058]FIG. 10 is a perspective view showing the construction of aprincipal part of a modified example of a magnetic head in the thirdembodiment;

[0059]FIG. 11 is a sectional view of the magnetoresistance effectelement in the third embodiment of the present invention, which isprovided with an auxiliary yoke;

[0060]FIG. 12(a) is a perspective view showing a magnetic field due tocurrent, which is generated when a sense current is caused to flow, andthe direction of a magnetic field due to bias based on a magneticallyhard film or an antiferromagnetic film, in the first embodiment of amagnetoresistance effect element according to the present invention, and

[0061]FIG. 12(b) is a characteristic graph of the magnitude of anannular magnetic field due to current, which is generated in amagnetoresistance effect film when a sense current of 5 mA is caused toflow, with respect to the distance from the center of a pillarelectrode;

[0062]FIG. 13(a) is a perspective view showing a magnetic field due tocurrent, which is generated when a sense current is caused to flow, andthe direction of a magnetic field due to bias based on a magneticallyhard film or an antiferromagnetic film, in the first embodiment of amagnetoresistance effect element according to the present invention, and

[0063]FIG. 13(b) is a characteristic graph of the magnitude of anannular magnetic field due to current, which is generated in amagnetoresistance effect film when a sense current of 5 mA is caused toflow, with respect to the distance from the center of a pillarelectrode;

[0064]FIG. 14 is a sectional view of the fourth embodiment of amagnetoresistance effect element according to the present invention;

[0065]FIG. 15 is a schematic diagram showing a modified example 4-1 of amagnetoresistance effect element in the fourth embodiment of the presentinvention, wherein the sectional area of a pillar electrode is linearlyvaried from one surface contacting a top electrode to the other surfacecontacting the magnetoresistance effect film;

[0066]FIG. 16 is a schematic diagram showing a modified example 4-2 of amagnetoresistance effect element in the fourth embodiment of the presentinvention, wherein the magnetoresistance effect element is capable ofbeing generally divided into two parts by the sectional area of a pillarelectrode;

[0067]FIG. 17 is a schematic view of the fifth embodiment of amagnetoresistance effect element according to the present invention;

[0068]FIG. 18 is a schematic view of the sixth embodiment of amagnetoresistance effect element according to the present invention;

[0069]FIG. 19 is a plan view of a magnetoresistance effect element whena CPP type GMR film is mounted on a planar yoke head, wherein amagnetization distribution in a yoke and a magnetization free layer isdescribed by arrows and a traveling direction of a magnetic flux due tosignal in the case of the magnetization distribution is shown,

[0070]FIG. 19(a) showing a magnetization distribution and the flow of amagnetic flux due to signal when the influence of a magnetic field dueto a sense current flowing through a pillar electrode can be ignored,

[0071]FIG. 19(b) showing a magnetization distribution and the flow of amagnetic flux due to signal when the sense current of the columnelectrode can not be ignored, and

[0072]FIG. 19(c) showing the flow of a magnetic flux due to signal whenthe sense current of the pillar electrode can not be ignored, and theposition and shape of the pillar electrode suitable therefor, as theseventh embodiment of the present invention;

[0073]FIG. 20 is a perspective view of the eighth embodiment of amagnetoresistance effect element according to the present invention;

[0074]FIG. 21 is a plan view of the eighth embodiment of amagnetoresistance effect element according to the present invention,wherein a magnetization distribution in a yoke and a magnetization freelayer, the flow of a magnetic flux due to signal determined by thedistribution, and the position and shape of a pillar electrode suitablefor the flow are shown;

[0075]FIG. 22 is an illustration showing the details of the shape of thepillar electrode shown in FIG. 21;

[0076]FIG. 23 is an illustration for explaining the sectional shape of apillar electrode of a magnetoresistance effect element when the seventhand eighth embodiments of the present invention are combined;

[0077]FIG. 24 is a perspective view of the ninth embodiment of amagnetoresistance effect element according to the present invention;

[0078]FIG. 25 is a plan view of a top electrode in the ninth embodimentof the present invention, wherein current paths and a magnetic field dueto current generated in a magnetoresistance effect film by the currentpaths are shown by arrows;

[0079]FIG. 26 is a perspective view of a modified example 9-1 of amagnetoresistance effect film, wherein the top and bottom electrodes inthe ninth embodiment of the present invention are narrowed at theposition of a pillar electrode;

[0080]FIG. 27 is an illustration wherein current paths in a topelectrode in a modified example of the present invention, and a magneticfield due to current generated in a magnetoresistance effect film by thecurrent paths are shown by arrows;

[0081]FIG. 28 is a perspective view illustrating the schematicconstruction of a principal part of a magnetic reproducing systemaccording to the present invention;

[0082]FIG. 29 is an enlarged perspective view of a magnetic headassembly in front of an actuator arm 155, viewed from the side of adisk;

[0083]FIG. 30(a) is a conceptual drawing showing the relationshipbetween a head slider 153 and a magnetic head 200 when a flying heightis a predetermined positive value, and

[0084]FIG. 30(b) is a conceptual drawing showing the relationshipbetween such a “contact traveling” the head slider 153 and the magnetichead 200; and

[0085]FIG. 31 is a schematic perspective view showing the constructionof a principal part of a planar type head.

DESCRIPTION OF THE EMBODIMENTS

[0086] Referring now to the accompanying drawings, the embodiments ofthe present invention will be described below.

[0087] (First Embodiment)

[0088] First, as the first embodiment of the present invention, thebasic construction for restricting a current applying region to an MRfilm will be described below.

[0089]FIG. 1 is a conceptual drawing showing the construction of aprincipal part of a magnetoresistance effect element in this embodiment.That is, FIG. 1(a) is its sectional view, and FIG. 1(b) is its planview. The right side in FIG. 1 corresponds to an external magnetic fieldapproaching surface. For example, if the magnetoresistance effectelement is mounted on a shielded head, the external magnetic fieldapproaching surface is arranged so as to face a magnetic recordingmedium, and if the magnetoresistance effect element is mounted on aplanar type head, the external magnetic field approaching surface issupported on one of magnetic yokes.

[0090] In this embodiment, an MR element 10 comprises a bottom electrode12, a magnetoresistance effect film 13, a pillar electrode 14 and a topelectrode 15 which are stacked on a substrate 11 in that order. Theseare surrounded by an insulating material (not shown). Themagnetoresistance effect film 13 has a stacked construction wherein amagnetization fixed layer (pinned layer), non-magnetic intermediatelayer (spacer layer) and magnetization free layer (free layer) (notshown) are stacked. One embodiment of the present invention ischaracterized in that the sectional area of the pillar electrode 14 issmaller than the sectional area of each of the layers constituting themagnetoresistance effect film 13.

[0091] A sense current is caused to flow from the top electrode 15 tothe pillar electrode 14, the magnetoresistance effect film 13 and thebottom electrode 12, or in the opposite direction thereto. That is, withrespect to the magnetoresistance effect film 13, the sense current flowsin a direction perpendicular to the plane of the film.

[0092] Although the magnetoresistance effect film 13 is basically madeof a metal, most of the sense current flows through a region contactingthe pillar electrode 14. By utilizing this, an active region 13A can bedefined by the sectional shape of the pillar electrode 14.

[0093] Although the shape of the active region 13A in which the pillarelectrode 14 contacts the magnetoresistance effect film 13 may be anyshape, it is effectively a shape approximating to a rectangle as shownin FIG. 1(b) in order to efficiently read a magnetic field due to signalfrom a magnetic recording medium.

MODIFIED EXAMPLE 1-1

[0094]FIG. 2 is a conceptual drawing showing a first modified example ofa magnetoresistance effect element in this embodiment. That is, FIG.2(a) is its sectional view, and FIG. 2(b) is its plan view.

[0095] As shown in FIG. 2, the magnetoresistance effect element 10A inthis modified example comprises a bottom electrode 12, a pillarelectrode 14, a magnetoresistance effect film 13 and a top electrode 15which are stacked on a substrate 11 in that order. In such amagnetoresistance effect element, an active region 13A can be similarlydefined.

[0096] Although the shape of the active region 13A in which the pillarelectrode 14 contacts the magnetoresistance effect film 13 may be anyshape, it is effectively a shape approximating to a rectangle as shownin FIG. 2(b) in order to efficiently read a magnetic field due to signalfrom a magnetic recording medium.

MODIFIED EXAMPLE 1-2

[0097]FIG. 3 is a conceptual drawing showing a second modified exampleof a magnetoresistance effect element in this embodiment. That is, FIG.2(a) is its sectional view, and FIG. 2(b) is its plan view. Themagnetoresistance effect element 10B in this modified example comprisesa bottom electrode 12, a bottom pillar electrode 14A, amagnetoresistance effect film 13, a top pillar electrode 14B and a topelectrode 15 which are stacked on a substrate 11 in that order.

[0098]FIG. 4 is a conceptual drawing showing a current path in themagnetoresistance effect element 13.

[0099] In the magnetoresistance effect elements shown in FIGS. 1 and 2,a component parallel to the plane of the magnetoresistance effect film13 is generated in a current distribution in the film as shown in FIG.4(a), so that the element is not a complete CPP type MR element.

[0100] As compared with this, in the second modified example shown inFIG. 3, the component parallel to the plane of the magnetoresistanceeffect film 13 disappears in the current distribution in the film asshown in FIG. 4(b), so that the CPP type MR element can be extracted. Inaddition, the active region 13A of the magnetoresistance effect film canbe more effectively defined.

[0101] Although the shape of the active region 13A in which the toppillar electrode 14B and the bottom pillar electrode 14A contact themagnetoresistance effect film 13 may be any shape, it is effectively ashape approximating to a rectangle as shown in FIG. 3(b) in order toefficiently read a magnetic field due to signal from a magneticrecording medium.

MODIFIED EXAMPLE 1-3

[0102]FIG. 5 is a conceptual drawing showing a sectional construction ofa third modified example of a magnetoresistance effect element in thisembodiment. That is, in the magnetoresistance effect element 10C in thismodified example, a non-magnetic intermediate layer 13S of a spin-valvewhich has a stacked film 13P having at least one magnetization fixedlayer (pinned layer) and a stacked film 14F having at least onemagnetization free layer (free layer) is patterned in the form of apillar. However, the stacking order in this figure should not limited.Furthermore, electrodes (not shown) contact the top and bottom faces ofthe magnetoresistance effect film 13.

[0103] The interface between the non-magnetic intermediate layer 13S andthe magnetization fixed layer and the interface between the non-magneticintermediate layer 13S and the magnetization free layer have theinterfacial effect of the magnetoresistance effect. In the element shownin FIG. 5, a current flows in a direction substantially perpendicular tothese interfaces, so that the effects of a CPP type GMR can beextracted.

[0104] Although the shape of the active region in which the pillarspacer layer 13S contacts the pinned layer 13P and the free layer 13Smay be any shape, it is effectively a shape approximating to a rectanglein order to efficiently read a magnetic field due to signal from amagnetic recording medium.

[0105] (Second Embodiment)

[0106] As the second embodiment of the present invention, an embodimentof the structure shown in FIG. 1 which is applied to a shielded headwill be described below.

[0107]FIG. 6 is a conceptual drawing showing a principal part of ashielded head on which the magnetoresistance effect element illustratedin FIG. 1 is mounted. That is, FIG. 6(a) is a sectional view taken alonga longitudinal direction of a recording track, and FIG. 6(b) is asectional view taken along across direction of a recording track. In thefigure, a magnetic recording medium 200 travels in directions of arrowA.

[0108] In the magnetic head in this embodiment, a magnetoresistanceeffect film 13 is sandwiched between a pair of magnetic shields 24 and24, and is arranged so as to be perpendicular to the magnetic recordingmedium 200. In addition, a top electrode 12, a pillar electrode 14 and atop electrode 15 are provided as shown in the figure, so that an activeregion 13A is defined.

[0109]FIG. 7 is a conceptual drawing a magnetization distribution in amagnetization free layer (free layer) of the magnetoresistance effectfilm 13. A magnetic flux due to signal from the recording medium 13enters the magnetization free layer of the magnetoresistance effectelement 13 to rotate the magnetization of the magnetization free layer.Usually, in no magnetic field, as shown in FIG. 7(a), the magnetization(arrows) of the magnetization free layer is formed as a single magneticdomain by a magnetic field due to bias from a biasing film 30 so as tobe perpendicular to an approaching magnetic field. If a magnetic flux Fenters herein from the recording medium, the magnetization (arrows) ofthe magnetization free layer rotates as shown in FIG. 7(b), but therotation angle thereof attenuates as the distance from the recordingmedium 200 increases. That is, the sensitivity is higher in a portionnearer to the recording medium 200.

[0110] Therefore, if the pillar electrode 14 is arranged in a portionnearer to the recording medium 200, only a portion having a highsensitivity of the magnetization free layer can be an active region 13A,so that it is possible to realize a high output.

[0111] Furthermore, in the construction of FIG. 6, each of the topelectrode 15 and the bottom electrode 12 may also serve as a magneticshield. In that case, the structure is simplified, and the fabricatingprocess is shortened.

[0112] In FIG. 6, the magnetoresistance effect element may be an elementin the above described modified example 1-1, 1-2 or 1-3.

[0113] (Third Embodiment)

[0114] As the third embodiment of the present invention, a planar yokehead having a bias applying means will be described below.

[0115]FIG. 8 is a perspective view showing the construction of a planaryoke head on which the magnetoresistance effect element illustrated inFIG. 1 is mounted. In this figure, the same reference numbers are givento the same element as those described above referring to FIGS. 1through 7 and 31 to omit the detailed descriptions thereof. Furthermore,in this figure, top and bottom electrodes in a portion parallel to theplane of the film are omitted.

[0116] In this embodiment, a pair of yokes 20, 20 are sandwiched betweena pair of biasing films 30 and 30 formed of a hard film of amagnetically hard material or an antiferromagnetic film, and themagnetization is formed as a single magnetic domain so as to be directedin a direction of y. Similarly, the magnetization of the magnetizationfree layer of a magnetoresistance effect film 13 is also aligned withthe direction of y.

[0117]FIG. 9 is a conceptual drawing showing a magnetizing direction inthe head in this embodiment.

[0118] As shown in this figure, a magnetic flux from a magneticrecording medium 200 mainly enters the yoke 20 in a portion above atrack 200T, and the magnetization of the magnetization free layer isalso greatly rotate only in the portion above the track 200T. Therefore,if the sectional area of a pillar electrode 14 is limited to a trackwidth 200W as shown in FIG. 8 so that only a portion having a highsensitivity is an active region 13A (see FIG. 1), it is possible toimprove the output.

[0119] Furthermore, also in this embodiment, the same effects can beobtained even if the magnetoresistance effect element in the abovedescribed modified example 1-1, 1-2 or 1-3 is mounted.

MODIFIED EXAMPLE 3-1

[0120] As a first modified example of this embodiment, a constructionfor applying a magnetic field due to bias to a yoke and a magnetizationfree layer will be described below.

[0121]FIG. 10 is a schematic perspective view showing the constructionof a principal part of a magnetic head in this modified example. Also inthis figure, the same reference numbers are given to the same elementsas those described above referring to FIGS. 1 through 9 and 31 to omitthe detailed descriptions thereof.

[0122] In this modified example, a pair of biasing films 30, 30 of amagnetically hard film or an antiferromagnetic film are arranged onyokes 20 and a magnetization free layer. According to such a “patternedbias construction”, an ideal magnetic field due to bias can be appliedto the yokes 20 and the magnetization free layer.

MODIFIED EXAMPLE 3-2

[0123] As a second modified example of this embodiment, a constructionhaving auxiliary yokes will be described below.

[0124]FIG. 11 is a schematic sectional view showing the construction ofa principal part of a magnetic head in this modified example. Also inthis figure, the same reference numbers are given to the same elementsas those described above referring to FIGS. 1 through 10 and 31 to omitthe detailed descriptions thereof.

[0125] In this modified example, auxiliary yokes 22 substantially havingthe same size as that of the width 200W of a recording track of arecording medium are added to the planar yoke head illustrated in FIG.8. Thus, a magnetic flux due to signal from the recording track isefficiently led to the yokes 20, and thus to the magnetization freelayer of a magnetoresistance effect element 13. As a result, only themagnetization of a portion above the recording track ideally rotates, sothat an active region 13A can be more conspicuously defined by arranginga pillar electrode 14 within the track width.

[0126] Of course, the same effects can be obtained even if theconstruction illustrated in any one of FIGS. 10, 20, 24 and 26 isprovided with the same auxiliary yokes 22, 22.

[0127] (Fourth Embodiment)

[0128] As the fourth embodiment of the present invention, a concreteconstruction for suppressing the effects of an annular magnetic fieldgenerated by a pillar electrode will be described below.

[0129]FIG. 12(a) is a schematic diagram showing a principal part of themagnetoresistance effect element illustrated in FIG. 1. Biasing films 30of a magnetically hard film or an antiferromagnetic film are provided onthe front and rear sides in the figure, so that the magnetization freelayer is formed as a single magnetic domain by a magnetic field due tobias generated by the biasing films 30.

[0130] It is assumed that the cross section of the pillar electrode 14is circular and its height is infinitely long. If a sense current Is iscaused to flow through such a pillar electrode 14 in a direction ofarrow, an annular magnetic field due to current is applied to themagnetoresistance effect element 13 as shown by arrow M. If the magneticfield M due to current increases to such an extent that it can not beignored, the magnetic permeability of a magnetic flux due to signalentering the magnetization free layer in a lateral direction in thefigure is not uniform on the plane. Moreover, if the magnitude of themagnetic field M due to current exceeds the magnetic field B due tobias, the magnetization of the magnetization free layer rotates.

[0131]FIG. 12(b) is a graph showing the magnitude of a magnetic field Mdue to current at a position, which is spaced from the center of thepillar electrode 14 by a distance r, when a sense current Is of 5 mA iscaused to flow. Furthermore, in this figure, the broken lines show amagnetic field distribution in the pillar electrode 14, and the solidline shows a magnetic field distribution outside of the pillar electrode14. That is, the magnetic field due to current increases in the pillarelectrode 14 as the distance from the center increases, has a peak onthe outer wall of the electrode 14, and attenuates as the distance fromthe outer wall of the electrode 14 increases outwardly.

[0132] The locally applied maximum magnetic field greatly depends on theradius r_(p) of the pillar electrode 14. For example, the maximummagnetic field is 25 Oe if the radius is 100 nm, it is 12.5 Oe if theradius is 200 nm, and it is 8.3 Oe if the radius is 300 nm. Thus, themaximum magnetic field due to current decreases as the radius r_(p)increases. It can be therefore said that the radius r_(p) of the pillarelectrode 14 is preferably as large as possible.

[0133]FIG. 13(a) is a schematic diagram showing a principal part of themagnetoresistance effect element illustrated in FIG. 1. In this case,biasing films 30 of a magnetically hard film or an antiferromagneticfilm are provided on the front and rear sides in the figure, so that themagnetization free layer is formed as a single magnetic domain by amagnetic field due to bias generated by the biasing films 30.

[0134] It is herein assumed that an infinitely thin linear electrode. Ifa sense current Is is caused to flow through such a linear electrode ina direction of arrow, an annular magnetic field is applied to themagnetoresistance effect element 13 as shown by arrow M. If the magneticfield M due to current increases to such an extent that it can not beignored, the magnetic permeability of a magnetic flux F due to signalentering the magnetization free layer in a lateral direction in thefigure is not uniform on the plane. Moreover, if the magnetic field Mdue to current exceeds the magnetic field B due to bias, themagnetization of the magnetization free layer rotates.

[0135]FIG. 13(b) is a graph showing the magnitude of a magnetic field Mdue to current at a position, which is spaced from the pillar electrode14 by a distance r, when a sense current of 5 mA is caused to flow. Themagnitude of the magnetic field M due to current greatly depends on theheight h of the pillar electrode 14. For example, at a position of r=0.2μm, the magnitude of the magnetic field M due to current is 1.25 Oe ifthe height h is 10 nm, it is 7.18 Oe if the height h is 60 nm, and it is17.7 Oe if the height h is 200 nm. Thus, the magnitude of the magneticfield M due to current decreases as the height h increases. Because theintensity of the magnetic field M due to current at the position of themagnetoresistance effect film 13 is determined by the integral alonglongitudinal directions of the pillar electrode 14. It can be thereforesaid that the height h of the pillar electrode 14 must be designed to besmallish.

[0136] In view of the foregoing, the pillar electrode 14 is designed asfollows.

[0137] First, the pillar electrode 14 must be thick in order to suppressthe magnetic field M due to current. On the other hand, the sectionalarea of the pillar electrode 14 on a plane contacting themagnetoresistance effect film 13 is preferably small from the standpointof the narrowing of the active region 13A and from the standpoint of theenhancement of the resistance of the CPP type GMR element.

[0138] In addition, the magnetic field M due to current can be reducedas the length of the pillar electrode 14 decreases. However, the heighth of the pillar electrode 14 must be at least about 100 nm in order toensure the electrical insulation between the magnetoresistance effectfilm 13, the top electrode 15 and the bottom electrode 12.

[0139] As a design simultaneously satisfying these conditions, forexample, in the case of the magnetoresistance effect element illustratedin FIG. 1, the sectional area of a portion of the pillar electrode 14near the top electrode 15 may be large, and the sectional area of aportion of the pillar electrode 14 near the magnetoresistance effectfilm 13 may be small.

[0140]FIG. 14 is a conceptual drawing illustrating this construction. Itcan be also seen from FIG. 12 that the magnetic field due to current issmall in a portion 14L having a large sectional area even if its heightis large. Therefore, only the magnetic field M due to current from aportion 14S having a narrowed sectional area near the magnetoresistanceeffect film 13 may be substantially considered. In this case, the crosssection in horizontal directions may have a shape of circle, or any oneof other various shapes as will be described later in detail.

[0141] An example where this pillar electrode 14 is applied to themodified example 1-2 is shown in FIG. 14(b). This example is moreeffective since the contribution of two pillar electrodes is moderated.

[0142] This pillar electrode 14 can be also applied to themagnetoresistance effect element in the modified example 1-1. Since therotation of magnetization according to a magnetic field due to signalfrom a magnetic recording medium is carried out in a magnetization freelayer, if the area of a pillar non-magnetic intermediate layercontacting the magnetization free layer is smaller than the area of thepillar non-magnetic intermediate layer contacting a magnetization fixedlayer as shown in FIG. 14(c), it is possible to enhance its sensitivity.

[0143] In addition, if the area of the pillar non-magnetic intermediatelayer contacting the magnetization fixed layer is smaller than the areaof the pillar non-magnetic intermediate layer contacting themagnetization free layer as shown in FIG. 14(d), unnecessary magneticfield is not applied to the magnetization fixed layer, so that it ispossible to improve the magnetization stability in the magnetizationfixed layer.

MODIFIED EXAMPLE 4-1

[0144]FIG. 15 is a conceptual drawing showing a construction wherein thesectional area of the pillar electrode 14 is linearly varied from onesurface contacting the top electrode 15 to the other surface contactingthe magnetoresistance effect film 13. Such a pillar electrode 14 can beprepared by one lift off if a tapered resist is used. Of course, thispillar electrode 14 can also be applied to the magnetoresistance effectelement in any one of the modified example 1-1 and 1-2.

[0145] An example where this pillar electrode 14 is applied to themodified example 1-2 is shown in FIG. 15(b). This example is moreeffective since the contribution of two pillar electrodes is moderated.

[0146] This pillar electrode 14 can be also applied to themagnetoresistance effect element in the modified example 1-1. Since therotation of magnetization according to a magnetic field due to signalfrom a magnetic recording medium is carried out in a magnetization freelayer, if the area of a pillar non-magnetic intermediate layercontacting the magnetization free layer is smaller than the area of thepillar non-magnetic intermediate layer contacting a magnetization fixedlayer as shown in FIG. 15(c), it is possible to enhance its sensitivity.

[0147] In addition, if the area of the pillar non-magnetic intermediatelayer contacting the magnetization fixed layer is smaller than the areaof the pillar non-magnetic intermediate layer contacting themagnetization free layer as shown in FIG. 15(d), unnecessary magneticfield is not applied to the magnetization fixed layer, so that it ispossible to improve the magnetization stability in the magnetizationfixed layer.

MODIFIED EXAMPLE 4-2

[0148]FIG. 16 is a conceptual drawing illustrating a constructionwherein the sectional area of the pillar electrode 14 is generallydivided into two stages. Thus, it is possible to increase the differencebetween the area S_(MR) of a surface of the pillar electrode 14contacting the magnetoresistance effect film 13 and the areaS_(upperlead) of a surface of the pillar electrode 14 contacting the topelectrode 15. As this difference increases, the magnetic field M due tocurrent from a portion of the pillar electrode 14 having a largesectional area can be reduced. By the inventor's study, it was revealedthat the pillar electrode 14 is preferably designed so thatS_(upperlead)/S_(MR)>2000.

[0149] However, even if the pillar electrode 14 is thus designed, if theportion having the small sectional area is long, the magnetic field Mdue to current increases as described above referring to FIGS. 13(a) and13(b). Therefore, the height of the portion having the small sectionalarea is preferably 30 nm or less, and more preferably 15 nm or less.

[0150] An example where this pillar electrode 14 is applied to themodified example 1-2 is shown in FIG. 16(b). This example is moreeffective since the contribution of two pillar electrodes is moderated.

[0151] This pillar electrode 14 can be also applied to themagnetoresistance effect element in the modified example 1-1. Since therotation of magnetization according to a magnetic field due to signalfrom a magnetic recording medium is carried out in a magnetization freelayer, if the area of a pillar non-magnetic intermediate layercontacting the magnetization free layer is smaller than the area of thepillar non-magnetic intermediate layer contacting a magnetization fixedlayer as shown in FIG. 16(c), it is possible to enhance its sensitivity.

[0152] In addition, if the area of the pillar non-magnetic intermediatelayer contacting the magnetization fixed layer is smaller than the areaof the pillar non-magnetic intermediate layer contacting themagnetization free layer as shown in FIG. 16(d), unnecessary magneticfield is not applied to the magnetization fixed layer, so that it ispossible to improve the magnetization stability in the magnetizationfixed layer.

[0153] (Fifth Embodiment)

[0154] As the fifth embodiment of the present invention, a constructionwherein the magnetic field due to current in a pillar electrode iscanceled.

[0155]FIG. 17 is a conceptual drawing illustrating the construction of aprincipal part of a magnetoresistance effect element in this embodiment.That is, FIG. 17(a) is a drawing of its longitudinal section, and FIG.17(b) is a drawing of horizontal section of its principal part.

[0156] This embodiment is characterized in that, in the constructionillustrated in FIG. 1, the pillar electrode 14 is divided into a centralconductive portion 14C and an outer peripheral conductive portion 14P,and a sense current Is is caused to go and return to cancel a magneticfield M due to current. The central conductive portion 14 and the outerperipheral conductive portion 14P are insulated from each other by meansof an insulator 14I.

[0157] The sense current Is flows from a top electrode approach route12A into the central conductive portion 14C to be applied to themagnetoresistance effect film 13 in a direction perpendicular thereto.Then, the sense current Is flows from a bottom electrode approach route12A to a return route 12B arranged on the magnetoresistance effect filmto pass through the outer peripheral conductive portion 14P to a topelectrode return route 15B. Of course, the sense current Is may flow inthe opposite direction. If the sense current Is is thus caused go andreturn in the pillar electrode 14, the magnetic field M due to currentapplied to the magnetoresistance effect film 13 can be reduced, and canbe ideally zero. of course, this can also be similarly applied to themodified examples 1-1 and 1-2 illustrated in FIGS. 2 and 3.

[0158] (Sixth Embodiment)

[0159] As the sixth embodiment of the present invention, a constructionwherein a magnetic field due to current in a pillar electrode isshielded will be described below.

[0160]FIG. 18 is a conceptual drawing illustrating the construction of aprincipal part of a magnetoresistance effect element in this embodiment.That is, FIG. 18(a) is a drawing of its longitudinal section, and FIG.18(b) is a drawing of horizontal section of its principal part.

[0161] In this embodiment, a magnetic shield 15 is arranged around apillar electrode 14 via an insulator 14I. If such a magnetic shield 15is provided, the magnetic field M due to current applied to themagnetoresistance effect film 13 can be reduced, and can be ideallyzero.

[0162] (Seventh Embodiment)

[0163] In the fourth through sixth embodiments, the design of theelement for reducing or suppressing the influence of the annularmagnetic field M due to current from the pillar electrode has beendescribed.

[0164] This embodiment relates to an approach to the avoidance of acrosstalk from an adjacent track during reading, which is caused by amagnetic field M due to current.

[0165]FIG. 19 is a conceptual drawing showing a plane construction of aplanar yoke head on which a CPP type GMR element is mounted.

[0166]FIG. 19(a) shows a magnetization distribution (arrows) when theinfluence of a magnetic field M due to current is small to an extentthat it can be ignored. Biasing films 30, 30 of a magnetically hard filmor an antiferromagnetic film are provided, so that each of themagnetization free layer 13F of a magnetoresistance effect film andyokes 20 is formed as a single magnetic domain by a magnetic field B dueto bias generated by the biasing films 30, 30. Thus, the magneticpermeability with respect to a track longitudinal direction T in anyportion of the magnetization free layer 13F and the yokes 20 is maximum,so that magnetization enters only in the track longitudinal direction T.In addition, the magnetic permeability on the track is maximum, so thatonly the magnetization on the track clearly rotates.

[0167]FIG. 19(b) shows a magnetization distribution when a refluxcurrent M remains to have the same intensity as that of a magnetic fieldB due to bias. In this case, the magnetization (arrows) of themagnetization free layer 13F and the yokes 20 rotates as shown in thefigure. At this time, the magnetization (arrows) is deviated from thecross direction of the track 200T in a portion deviated from the track200T, so that the direction of a high magnetic permeability is not thetrack longitudinal direction in some place. At this time, there is somepossibility that a magnetic flux F due to signal from an adjacent sidetrack 200ST may enter in a direction perpendicular to magnetization togenerate a crosstalk to deteriorate off track characteristics. In otherwords, the magnetization distribution of the magnetization free layer13F and the yokes 20 is changed by the magnetic field M due to currentto form a magnetic permeable lens, so that the magnetic flux from theadjacent track also converges.

[0168] In order to prevent the readout of such a converging magneticflux from the adjacent track, the cross section of the pillar electrode14 may have a shape of trapezoid as illustrated in FIG. 19(c). Thus, themagnetic flux F from the side track does not enter the active region 13Aof the magnetoresistance effect film, so that off track characteristicsare improved.

[0169] In this case, when the direction of the magnetic field B due tobias is +y direction and when the direction of the sense current Is is−z direction, the positional relationship is required so that theshorter side of the trapezoid is arranged on the side of +x and thelonger side thereof is arranged on the side of −x.

MODIFIED EXAMPLE 7-1

[0170] If the shape of the cross section of the pillar intermediatenon-magnetic film 13S in the modified example 1-3 illustrated in FIG. 5is the same trapezoid as that illustrated in FIG. 19, off trackcharacteristics can be improved.

[0171] (Eighth Embodiment)

[0172] When a magnetoresistance effect film is mounted on a planar yokehead, if the distance between the magnetization free layer of themagnetoresistance effect film and yokes is shortened, the flow of amagnetic flux due to signal is smooth. If a vertically current applyingmagnetoresistance effect film is mounted, a bottom electrode is arrangedtherebetween, so that the distance between the magnetization free layerand the yokes is relatively long.

[0173] On the other hand, this embodiment relates to a design whereinthe distance between a magnetization free layer and yokes is decreased.

[0174]FIG. 20 is a schematic perspective view showing the constructionof a principal part of a magnetic head in this embodiment. Also in thisfigure, the same reference numbers are given to the same element asthose described above referring to FIGS. 1 through 19 and 31 to omit thedetailed descriptions thereof.

[0175] If a bottom electrode 12 is arranged in a gap between yokes 20and 20 as shown in this figure, the distance between a magnetoresistanceeffect film 13 and the yokes 20. Furthermore, a pair of biasing films ofa magnetically hard film or an antiferromagnetic film for applying amagnetic field due to bias to the yokes 20 and the magnetization freelayer 13F in y direction are provided in the front and rear sides in thefigure although they are not shown in FIG. 20.

[0176] In the construction of FIG. 20, there is a problem in that themagnetic field due to current from a bottom electrode 12 is applied tothe magnetoresistance effect film 13 and the yokes 20. For example, if asense current Is is caused to flow through a pillar electrode 14 in −zdirection, a magnetic field M due to current is generated in +xdirection.

[0177] On the other hand, if a top electrode 15 is arranged in parallelto the bottom electrode 12 as shown in the figure so that the sensecurrent goes and returns, the magnetic field M due to current appliedfrom the top electrode 15 to the bottom electrode 12 can besubstantially ignored.

[0178] However, the magnetic field due to current applied to themagnetoresistance effect film 13 is further increased, so that themagnetization (arrows) rotates particularly in the central portion ofthe element to have an x component as shown in the magnetizationdistribution of FIG. 21. Since the magnetic permeability in a directionperpendicular to the direction B of magnetization in the biasing films30 is highest, the magnetic flux entering the yokes 20 on the straightin the track longitudinal direction (x direction) from a magneticrecording medium is bent in the magnetization free layer of themagnetoresistance effect film as shown by arrows in the figure. That is,the “skew” is caused in the magnetic flux F due to signal.

[0179] In view of this, if the shape of the horizontal cross section ofthe pillar electrode 14 is a parallelogram as shown in FIG. 21 and ifthe pillar electrode 14 is provided in a portion on which the magneticflux F due to signal from the track concentrates, the active region 13Aof the magnetoresistance effect film can be set at a sensitive place, sothat it is possible to obtain a high output.

[0180] Specifically, when the direction of the magnetic field B due tobias is +y direction and the direction of the sense current Is is −zdirection, the four vertexes of the parallelogram of the horizontalcross section of the pillar electrode 14 are designed so that B(a, −c),C(a, b) and D(0, b+c) assuming that A (0, 0) as shown in FIG. 22. Thatis, the shape of a surface of the pillar electrode 14 contacting themagnetoresistance effect film has an edge portion which is inclined froma direction perpendicular to the magnetizing direction of the yokes 20toward the magnetization rotating direction of the magnetization freelayer of the magnetoresistance effect film (sides DC and AB in thisexample). In addition, the pillar electrode 14 is arranged so as to beshifted from the center of the magnetoresistance effect film 13 in −ydirection.

MODIFIED EXAMPLE 8-1

[0181] It is more effective if the shape of the horizontal cross sectionof the pillar electrode 14 or the pillar intermediate non-magnetic layer13S (see FIG. 5) is combined with the seventh embodiment so as to be ashape having both characteristics of a parallelogram and a trapezoid.

[0182] That is, when the direction of the magnetic field B due to biasis +y direction and the direction of the sense current Is is −zdirection, the four vertexes may be designed so that B(a, −c), C(a, b)and D(0, d) (d>b+c) assuming that A (0, 0) as shown in FIG. 23. Also inthis case, the shape of a surface of the pillar electrode 14 contactingthe magnetoresistance effect film has an edge portion which is inclinedfrom a direction perpendicular to the magnetizing direction of the yokes20 toward the magnetization rotating direction of the magnetization freelayer of the magnetoresistance effect film (sides DC and AB in thisexample). In addition, the shape of a surface of the pillar intermediatenom-magnetic layer 13S contacting the stacked film 13P or the stackedfilm 13F has an edge portion which is inclined from a directionperpendicular to the magnetizing direction of the yokes 20 toward themagnetization rotating direction of the magnetization free layer of themagnetoresistance effect film (sides DC and AB in this example).

MODIFIED EXAMPLE 8-2

[0183] The concept of this embodiment can be applied to themagnetoresistance effect film 13 wherein the intermediate non-magneticlayer 13S is formed so as to have a pillar shape as illustrated in FIG.5. That is, if the pillar non-magnetic layer 13S is provided at aposition as shown in FIG. 22 or 23 so as to have a shape as showntherein, it is possible to obtain a high output.

[0184] (Ninth Embodiment)

[0185] When the bottom electrode is arranged in the gap between theyokes as the above described eighth embodiment, if the top electrode isarranged in parallel thereto and if the shape of the horizontal crosssection of the pillar electrode is the shape shown in FIG. 22, it ispossible to avoid the effects of the rotation of magnetization in themagnetization free layer, which is caused by the magnetic field due tocurrent from a portion other than the pillar electrode.

[0186] On the other hand, in this embodiment, a construction forpreventing the rotation of magnetization caused by such a magnetic fielddue to current.

[0187]FIG. 24 is a schematic perspective view showing the constructionof a principal part of a magnetic head in this embodiment. Also in thisfigure, the same reference numbers are given to the same elements asthose described above referring to FIGS. 1 through 23 and 31 to omit thedetailed explanations thereof.

[0188] In this embodiment, as illustrated in FIG. 24, a bottom electrode12 and a top electrode 15 are taken out in a longitudinal direction of arecording track 200T to cause a sense current Is to go and return. Thus,the direction of a magnetic field M due to current applied to amagnetization free layer 13F by the top electrode 15 and the bottomelectrode 12 can be the same as the direction of a magnetic field B dueto bias which is caused by a pair of biasing films (not shown).Specifically, if a sense current is applied to a pillar electrode 14 ina −z direction, the direction of the magnetic field M due to current is−y direction.

MODIFIED EXAMPLE 9-1

[0189] In fact, for example, a current distribution shown in FIG. 25 isformed in the top electrode 15 since the sense current Is concentrateson the pillar electrode 14. In this case, a current distribution in theopposite direction thereto is formed in the bottom electrode 12. Then,an annular magnetic field M due to current shown in FIG. 25 is generatedin the magnetoresistance effect film 13.

[0190] In order to avoid this, the top electrode 15 and the bottomelectrode 12 are provided current constriction regions 15 a and 12 a,respectively, as illustrated in FIG. 26. These current constrictionregions have a shape which is narrowed in the vicinity of the pillarelectrode 14. Thus, as shown in FIG. 27, the current distribution doesnot concentrate in the vicinity of the pillar electrode 14. For example,if a current is applied to the pillar electrode 14 in −z direction, thedirection of the magnetic field due to current applied to themagnetoresistance effect film 13 can be generally −y direction as shownin FIG. 27. Furthermore, only one of the top electrode 15 and the bottomelectrode 12 may be provided with the current constriction region.

[0191] (Tenth embodiment)

[0192] As the tenth embodiment of the present invention, a magneticreading system according to the present invention will be describedbelow. The magnetoresistance effect elements or the magnetic headsaccording to the first through the ninth embodiments of the presentinvention can be incorporated in, e.g., a recording/reproducing integralmagnetic head assembly, to be mounted in a magnetic reproducing system.

[0193]FIG. 28 is a perspective view of a principal part showing anexample of a schematic construction of such a magnetic recording system.That is, a magnetic recording and/or reproducing system 150 according totenth embodiment of the present invention is a system of a type in whicha rotary actuator is used. In this figure, a longitudinal recording orvertical recording magnetic disk 200 is mounted on a spindle 152, and isrotated in a direction of arrow A by means of a motor (not shown) whichis driven in response to a control signal from a drive unit control part(not shown). The magnetic disk 200 has a longitudinal recording orvertical recording layer. A head slider 153 for recording/readinginformation in the magnetic disk 200 is mounted on the tip of athin-film-like suspension 154. The head slider 153 has a magnetic head,which uses a magnetoresistance effect element in any one of the abovedescribed embodiment, in the vicinity of the tip thereof.

[0194] If the magnetic disk 200 rotates, the medium facing surface (ABS)of the head slider 153 is held so as to be spaced from the surface ofthe magnetic disk 200 by a predetermined flying height.

[0195] The suspension 154 is connected to one end of an actuator arm 155which has a bobbin portion for holding a driving coil (not shown). Onthe other end of the actuator arm 155, there is provided a voice coilmotor 156 which is a kind of linear motor. The voice coil motor 156comprises a driving coil (not shown) wound onto the bobbin portion ofthe actuator arm 155, and a magnetic circuit comprising a permanentmagnet and a facing yoke which face each other so as to sandwich thecoil therebetween.

[0196] The actuator arm 155 is held by ball bearings (not shown) whichare provided at two places above and below a fixed axis 157, and isrotatable and slidable by the voice coil motor 156.

[0197]FIG. 29 is an enlarged perspective view of a magnetic headassembly in front of the actuator arm 155 viewed from the side of adisk. That is, a magnetic head assembly 160 has an actuator arm 151having, e.g., a bobbin portion for holding a driving coil, and asuspension 154 is connected to one end of the actuator arm 155.

[0198] On the tip of the suspension 154, a head slider 153 having areading magnetic head using any one of the above describedmagnetoresistance effect elements referring to the first embodimentthrough the ninth embodiment is mounted. A recording head may becombined therewith. The suspension 154 has a lead wire 164 forwriting/reading signals. This lead wire 164 is electrically connected tothe respective electrodes of the magnetic head incorporated in the headslider 153. In the figure, reference number 165 denotes an electrode padof the magnetic head assembly 160.

[0199] Between the medium facing surface (ABS) of the head slider 153and the surface of the magnetic disk 200, a predetermined flying heightis set.

[0200]FIG. 30(a) is a conceptual drawing showing the relationshipbetween the head slider 153 and the magnetic disk 200 when the flyingheight is a predetermined positive value. As illustrated in this figure,in usual many magnetic recording systems, the slider 153 including themagnetic head 10 operates while flying at a predetermined height fromthe surface of the magnetic disk 200. According to the tenth embodimentof the present invention, such a “flying traveling type” magneticrecording system can also read at low noises with a higher resolutionthan conventional systems. That is, by adopting any one of the abovedescribed magnetoresistance effect elements referring to the firstembodiment through the ninth embodiment, weak magnetization informationfrom a track to be read can be surely read. That is, since it ispossible to reduce the cross talk from adjacent recording track, it ispossible to reduce the track pitch to greatly improve the recordingdensity.

[0201] On the other hand, if the recording density further increases, itis required to lower the flying height to glide the slider nearer to themagnetic disk 200 to read information. For example, in order to obtain arecording density of about 40 G (giga) bits per one square inch, thespacing loss due to the flying of the slider is too large, so that it isnot possible to ignore the problem of the collision of the head 10 withthe magnetic disk 200 due to the very low flying.

[0202] For that reason, a system for traveling the slider whilepositively causing the magnetic head 10 to contact the magnetic disk 200is also considered.

[0203]FIG. 30(b) is a conceptual drawing showing the relationshipbetween such a “contact traveling type” head slider 153 and the magneticdisk 200. The magnetic head according to the present invention can alsobe mounted on the “contact traveling type” slider by providing adiamond-like carbon (DLC) lubricating film on the contact surface to themedium. Therefore, the “contact traveling type” magnetic reading systemillustrated in FIG. 24(b) can also greatly reduce crosstalk fromadjacent tracks to greatly reduce the track pitch in comparison withconventional systems to stably carry out a recording/reading operationin a medium having a higher density.

[0204] As described above, referring to the accompanying drawings, thepresent invention has been described. However, the present inventionshould not be limited to those described in the respective examples.

[0205] For example, the material and the shape of elements of themagnetic head should not be limited to those described in the respectiveexamples, and the present invention can include all embodiments, whichcan be selected by persons with ordinary skill, to provide the sameeffects.

[0206] The magnetic reproducing system may be a reproducing only systemor a recording and/or reproducing system. In addition, the medium shouldnot be limited to a hard disk, but it may be any one of all magneticrecording media, such as flexible disks and magnetic cards. Moreover,the magnetic reproducing system may be a so-called “removable” typesystem wherein a magnetic recording medium is removed from the system.

[0207] As described above, according to the present invention, it ispossible to provide a magnetoresistance effect element capable ofprecisely defining the active region of an MR film in a CPP type MRelement and of effectively suppressing the influence of a magnetic fielddue to current from an electrode, and a magnetic head and magneticreproducing system using the same. Therefore, it is of great advantageto industry.

[0208] While the present invention has been disclosed in terms of theembodiment in order to facilitate better understanding thereof, itshould be appreciated that the invention can be embodied in various wayswithout departing from the principle of the invention. Therefore, theinvention should be understood to include all possible embodiments andmodification to the shown embodiments which can be embodied withoutdeparting from the principle of the invention as set forth in theappended claims.

What is claimed is:
 1. A magnetoresistance effect element comprising: amagnetization fixed layer in which the direction of magnetization issubstantially fixed to one direction; a magnetization free layer inwhich the direction of magnetization varies in response to an externalmagnetic field; and a non-magnetic intermediate layer formed between themagnetization fixed layer and the magnetization free layer, themagnetoresistance effect element having a resistance varying in responseto a relative angle between the direction of magnetization in themagnetization fixed layer and the direction of magnetization in themagnetization free layer, the film area of the non-magnetic intermediatelayer being smaller than the film area of each of the magnetizationfixed layer and the magnetization free layer, and a sense currentdetecting the variation of the resistance being applied to the filmplanes of the magnetization fixed layer, the non-magnetic intermediatelayer and the magnetization free layer in a direction substantiallyperpendicular thereto.
 2. A magnetoresistance effect element comprising:a stacked film including a magnetization fixed layer in which thedirection of magnetization is substantially fixed to one direction, anda magnetization free layer in which the direction of magnetizationvaries in accordance with an external magnetic field; and an electrodeconnected to a part of a principal plane of the stacked film, themagnetoresistance effect element having a resistance varying in responseto a relative angle between the direction of magnetization in themagnetization fixed layer and the direction of magnetization in themagnetization free layer, a sense current detecting the variation of theresistance being applied to the film planes of the magnetization fixedlayer and the magnetization free layer via the electrode in a directionsubstantially perpendicular to the magnetization fixed layer and themagnetization free layer, and the electrode comprising a pillarelectrode portion substantially perpendicularly extending from theprincipal plane of the stacked film, a first feed portion beingconnected to the pillar electrode portion and extending from the pillarelectrode portion substantially in parallel to the principal plane ofthe stacked film, and a second feed portion being connected to the firstfeed portion and extending from the first feed portion substantially inparallel to the principal plane.
 3. A magnetoresistance effect elementas set forth in claim 2, wherein the sectional area of the first feedportion substantially in parallel to the principal plane of the stackedfilm is greater than the sectional area of the pillar electrode portion,and is smaller than the sectional area of the second feed portion.
 4. Amagnetoresistance effect element as set forth in claim 2, wherein theshape of a contact surface of the principal plane of the stacked filmcontacting the pillar electrode portion is substantially aquadrilateral.
 5. A magnetoresistance effect element comprising: astacked film including a magnetization fixed layer in which thedirection of magnetization is substantially fixed to one direction, anda magnetization free layer in which the direction of magnetizationvaries in response to an external magnetic field; and two electrodes,each of which is connected to a part of a corresponding one of bothprincipal planes of the stacked film, the magnetoresistance effectelement having a resistance varying in response to a relative anglebetween the direction of magnetization in the magnetization fixed layerand the direction of magnetization in the magnetization free layer, asense current detecting the variation of the resistance being applied tothe film planes of the magnetization fixed layer and the magnetizationfree layer via the electrode in a direction substantially perpendicularto the magnetization fixed layer and the magnetization free layer, andeach of the two electrodes comprising a pillar electrode portionsubstantially perpendicularly extending from the corresponding one ofthe both principal planes of the stacked film, a first feed portionbeing connected to the pillar electrode portion and extending from thepillar electrode portion substantially in parallel to the both principalplanes of the stacked film, and a second feed portion being connected tothe first feed portion and extending from the first feed portionsubstantially in parallel to the both principal planes.
 6. Amagnetoresistance effect element as set forth in claim 5, wherein thesectional area of the first feed portion substantially in parallel tothe both principal planes of the stacked film is greater than thesectional area of the pillar electrode portion, and is smaller than thesectional area of the second feed portion.
 7. A magnetoresistance effectelement as set forth in claim 5, wherein the shape of a contact surfaceof each of the both principal planes of the stacked film contacting thepillar electrode portion is substantially a quadrilateral.
 8. Amagnetoresistance effect element comprising: a stacked film including amagnetization fixed layer in which the direction of magnetization issubstantially fixed to one direction, and a magnetization free layer inwhich the direction of magnetization varies in response to an externalmagnetic field; and an electrode connected to a part of a principalplane of the stacked film, the magnetoresistance effect element having aresistance varying in response to a relative angle between the directionof magnetization in the magnetization fixed layer and the direction ofmagnetization in the magnetization free layer, a sense current detectingthe variation of the resistance being applied to the film planes of themagnetization fixed layer and the magnetization free layer via theelectrode in a direction substantially perpendicular to themagnetization fixed layer and the magnetization free layer, and theelectrode comprising a pillar electrode portion substantiallyperpendicularly extending from the principal plane of the stacked film,and a feed portion extending substantially in parallel to the principalplane of the stacked film, the pillar electrode portion having twoconductive layers in the central portion and outer peripheral portionthereof, and the sense current being caused to flow in the oppositedirections to each other in the central portion and the outer peripheralportion.
 9. A magnetoresistance effect element comprising: a stackedfilm including a magnetization fixed layer in which the direction ofmagnetization is substantially fixed to one direction, and amagnetization free layer in which the direction of magnetization variesin response to an external magnetic field; and an electrode connected toa part of a principal plane of the stacked film, the magnetoresistanceeffect element having a resistance varying in response to a relativeangle between the direction of magnetization in the magnetization fixedlayer and the direction of magnetization in the magnetization freelayer, a sense current detecting the variation of the resistance beingapplied to the film planes of the magnetization fixed layer and themagnetization free layer via the electrode in a direction substantiallyperpendicular to the magnetization fixed layer and the magnetizationfree layer, and the electrode comprising a pillar electrode portionsubstantially perpendicularly extending from the principal plane of thestacked film, and a feed portion extending substantially in parallel tothe principal plane of the stacked film, the magnetoresistance effectelement further comprising a magnetic shield provided around the pillarelectrode portion.
 10. A magnetic head comprising: a pair of yokesarranged so as to face each other via a magnetic gap; and amagnetoresistance effect element magnetically coupled to the pair ofyokes, the pair of yokes having magnetization arranged in apredetermined direction, and the magnetoresistance effect elementcomprising: a stacked film including a magnetization fixed layer inwhich the direction of magnetization is substantially fixed to onedirection, and a magnetization free layer in which the direction ofmagnetization varies in response to an external magnetic field; and anelectrode connected to a part of a principal plane of the stacked film,the magnetoresistance effect element having a resistance varying inresponse to a relative angle between the direction of magnetization inthe magnetization fixed layer and the direction of magnetization in themagnetization free layer, a sense current detecting the variation of theresistance being applied to the film planes of the magnetization fixedlayer and the magnetization free layer via the electrode in a directionsubstantially perpendicular to the magnetization fixed layer and themagnetization free layer, and the shape of a connecting portion forconnecting the principal plane to the electrode having an edge portioninclined in a magnetization rotating direction of the magnetization freelayer from a direction perpendicular to the magnetizing direction of theyokes.
 11. A magnetic head as set forth in claim 10, wherein the shapeof the connecting portion for connecting the principal plane to theelectrode is asymmetric with respect to the center of the connectingportion.
 12. A magnetic head as set forth in claim 11, wherein the shapeof the connecting portion for connecting the principal plane to theelectrode is substantially a quadrilateral.
 13. A magnetic headcomprising: a pair of yokes arranged so as to face each other via amagnetic gap; and a magnetoresistance effect element magneticallycoupled to the pair of yokes, the pair of yokes having magnetizationarranged in a predetermined direction, and the magnetoresistance effectelement comprising: a first stacked film including a magnetization fixedlayer in which the direction of magnetization is substantially fixed toone direction; a second stacked film including a magnetization freelayer in which the direction of magnetization varies in response to anexternal magnetic field; and a non-magnetic intermediate layer providedbetween the first stacked layer and the second stacked layer, themagnetoresistance effect element having a resistance varying in responseto a relative angle between the direction of magnetization in themagnetization fixed layer and the direction of magnetization in themagnetization free layer, the area of a contact portion of a principalplane of the first stacked film contacting the non-magnetic intermediatelayer being smaller than the area of the principal plane of the firststacked film, and the area of a contact portion of a principal plane ofthe second stacked film contacting the non-magnetic intermediate layerbeing smaller than the area of the principal plane of the second stackedfilm, a sense current detecting the variation of the resistance beingapplied to the film planes of the magnetization fixed layer, thenon-magnetic intermediate layer and the magnetization free layer in adirection substantially perpendicular thereto, the shape of a connectingportion for connecting the non-magnetic intermediate layer to theprincipal plane of the first stacked film having an edge portioninclined in a magnetization rotating direction of the magnetization freelayer from a direction perpendicular to the magnetizing direction of theyokes.
 14. A magnetic head comprising: a pair of yokes arranged so as toface each other via a magnetic gap; and a magnetoresistance effectelement provided on the pair of yokes and magnetically coupled to thepair of yokes, the pair of yokes having magnetization arranged in apredetermined direction, and the magnetoresistance effect elementcomprising: a stacked film including a magnetization fixed layer inwhich the direction of magnetization is substantially fixed to onedirection, and a magnetization free layer in which the direction ofmagnetization varies in response to an external magnetic field; a topelectrode connected to a part of an upper principal plane of the stackedfilm; a bottom electrode connected to a lower principal plane of thestacked film, the magnetoresistance effect element having a resistancevarying in response to a relative angle between the direction ofmagnetization in the magnetization fixed layer and the direction ofmagnetization in the magnetization free layer, a sense current detectingthe variation of the resistance being applied to the film planes of themagnetization fixed layer and the magnetization free layer via theelectrode in a direction substantially perpendicular to themagnetization fixed layer and the magnetization free layer, the topelectrode having a pillar electrode portion substantiallyperpendicularly extending from the principal plane of the stacked film,and a feed portion extending substantially in parallel to the principalplane of the stacked film, the bottom electrode extending in a directionperpendicular to the direction of magnetization of the yokes, the feedportion of the top electrode being provided so that the sense currentflowing through the feed portion is anti-parallel to a sense currentflowing through the bottom electrode.
 15. A magnetic head as set forthin claim 14, wherein at least one of the top electrode and the bottomelectrode has a current constriction region at a position of a gapbetween the pair of yokes, the area of the current constriction regionbeing wider than a region of the pillar electrode contacting the stackedlayer.
 16. A magnetic head having a magnetoresistance effect element asset forth in claim
 1. 17. A magnetic head having a magnetoresistanceeffect element as set forth in claim
 2. 18. A magnetic head having amagnetoresistance effect element as set forth in claim
 5. 19. A magneticreproducing system which has a magnetic head as set forth in claim 16and which is capable of reading magnetic information stored in amagnetic recording medium.
 20. A magnetic reproducing system which has amagnetic head as set forth in claim 18 and which is capable of readingmagnetic information stored in a magnetic recording medium.